The present invention relates generally to satellite communication equipment and more particularly to an antenna alignment installation aid and diagnostic tool for a satellite user.
Dish antennas and receivers for audio/video transmission signals allow home viewers to receive television programming directly from satellite transmissions. The satellite dish antenna is typically secured to a mounting and must be aligned. Alignment involves physically boresighting the dish antenna so that its sensitive axis is directed at the broadcasting satellite.
The antenna dish is typically installed on the roof of a home, while the television is inside the home. In this arrangement, the antenna boresighting operation either requires two people to complete, or it requires an installer to travel back and forth between the antenna and the television several times, while trying to adjust the antenna for maximum signal reception.
For maximum signal reception, reasonably precise pointing of the antenna to the broadcast satellite is required. This task is not possible with visual boresighting. In the prior art, this task is accomplished by measuring the signal strength from the satellite as an indication of the precision pointing to the installer. It is also known to provide a visual indicator of the signal strength at the low noise block converter (LNB) of the satellite antenna. A light emitting diode presents a flashing rate to the installer that corresponds to the signal strength at the LNB. This method may not require the installer to go back and forth between television and the dish antenna, but is simply not capable of precise measurements.
Signal strength is not an accurate indication of the signal quality. However, it is typically not possible to measure signal quality parameters at the LNB without significant modifications to the LNB. In order to optimize the signal quality at the receiver, the quality of the signal must be used as an indicator and not merely the strength of a signal. It is possible to have a very strong signal that is poor quality. Prior art devices tend to correlate a strong signal with a quality signal and this is not always the case.
Another level is added to the complexity of the installation method when more than one satellite is involved in the system. For multiple satellites, the antenna position must be such that reception from all of the satellites is maximized. The simultaneous reception of signals from two or more satellites requires additional LNB""s on the antenna feed assembly. A balanced alignment among all the LNB""s is necessary. The installer must be skilled enough, or lucky enough, to adjust tilt, elevation and azimuth alignments for all of the LNB""s and minimize the number of trips back and forth between the antenna on the roof and the receiver in the house.
There is a need for a method and system that allows precision antenna orientation adjustments that can be made by a single user without making several trips between the satellite dish outside of a dwelling and the television inside the dwelling.
The present invention is a system and method for adjusting an antenna to maximize the quality of a program signal for at least two satellite locations. The present invention has a setup mode in an integrated receiver/decoder (IRD) where the IRD toggles between a first tone that correlates with a first LNB and a second tone that correlates with a second LNB. The toggling persists even after the IRD has acquired a signal lock on one of the LNB""s, allowing a signal lock to be acquired on the second LNB.
According to the present invention a simple circuit in the LNB monitors the signal output strength and produces an indicator when a peak has occurred. A summing circuit is used to indicate a master-lock for both LNB""s in which the peak detection of both signals is added. The IRD is used as a power source during the setup mode, thereby eliminating the need for and external battery pack while aligning the antenna.
An alternate embodiment of the present invention works in conjunction with signal feedback such as Pulse Width Modulation (PWM), tone detection and standard DiSEqC codes. DiSEqC is a European code developed to communicate between the antenna and the receiver to switch an LNB to a different satellite. The present invention uses signal feedback such as existing DiSEqC codes to determine the quality of the signal to the receiver. A quality signal has a low signal-to-noise ratio, while a strong signal has high amplitude. Therefore, the present invention is capable of measuring signal quality for antenna positioning instead of merely relying on signal strength.
It is an object of the present invention to precisely orient an antenna with at least two satellite locations. It is another object of the present invention to provide an indication of peak alignment using signal quality. It is still another object of the present invention to utilize existing DiSEqC codes as an indication of signal quality in the method and system of aligning an antenna with more than one satellite.
Other objects and advantages of the present invention will become apparent upon reading the following detailed description and appended claims, and upon reference to the accompanying drawings.